From: Alexander Nyberg <alexn@dsv.su.se>
This fixes a theoretical bug indicated in:
http://bugme.osdl.org/show_bug.cgi?id=240
It prevents overflow in case the required buffer is larger than the passed
buffer. This I found to be the minimally intrusive change.
Signed-off-by: Alexander Nyberg <alexn@dsv.su.se>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/parport/probe.c | 13 +++++++++++--
1 files changed, 11 insertions(+), 2 deletions(-)
diff -puN drivers/parport/probe.c~off-by-one-in-drivers-parport-probec drivers/parport/probe.c
--- 25/drivers/parport/probe.c~off-by-one-in-drivers-parport-probec 2004-12-01 23:18:59.675275416 -0800
+++ 25-akpm/drivers/parport/probe.c 2004-12-01 23:18:59.679274808 -0800
@@ -164,8 +164,16 @@ ssize_t parport_device_id (int devnum, c
if (retval != 2) goto end_id;
idlen = (length[0] << 8) + length[1] - 2;
- if (idlen < len)
+ /*
+ * Check if the caller-allocated buffer is large enough
+ * otherwise bail out or there will be an at least off by one.
+ */
+ if (idlen + 1 < len)
len = idlen;
+ else {
+ retval = -EINVAL;
+ goto out;
+ }
retval = parport_read (dev->port, buffer, len);
if (retval != len)
@@ -205,11 +213,12 @@ ssize_t parport_device_id (int devnum, c
buffer[len] = '\0';
parport_negotiate (dev->port, IEEE1284_MODE_COMPAT);
}
- parport_release (dev);
if (retval > 2)
parse_data (dev->port, dev->daisy, buffer);
+out:
+ parport_release (dev);
parport_close (dev);
return retval;
}
_